Homebrew PCBs

On Sat, 01 Jul 2006 17:12:30 +0200, fenrir_co <fenrir@...>  
wrote:

>  don't know why this is turning into such a debate - yes, starting
> with cupric chloride would probably work better - but if you've
> already got the FeCl3 and don't mind, or have learned to control the
> mess, regenerating is much cheaper.


I don't agree.
I'm no good with chemistry, but as i see it FeCl can not be regenerated as  
such with H2O2 and HCl, simply because those chemicals contain no iron. So  
i think what you are really doing is adding some CuCl etchant to the spent  
FeCl.

If that's the case then it makes much more sense to replace the spent FeCl  
with water (which would be just as effective - if i'm right) and make a  
normal CuCl of it. It will cost the same, unless you count the cost of tap  
water.

BTW, if things heat up you use too much H2O2, it is a well known effect  
with CuCl. It's basically just wasting chemicals because all gas escaping  
is lost to the etchant (and the gas bubbling goes hand in hand with the  
heat, although i wouldn't be able to explain it)

ST